Mixed fuel control system for a rocket motor



May 17, s ALLEN ETAL MIXED FUEL CONTROL SYSTEM FOR A ROCKET MOTOR Filed Aug. 5, 1951 s Sheets-Sheet 1 V IYVMTOISI S/b/ym 'ALZEA/ DfN Y/S HM? De /v y 17, 1955 s. ALLEN EIAL MIXED FUEL CONTROL SYSTEM FOR A ROCKET MOTOR Filed Aug. 5, 1951 3 Sheets-Sheet 2 11 VE/V T P5 5/0015 y ,4 11,6

May 17, 1955 s. ALLEN ETAL MIXED FUEL CONTROL SYSTEM FOR A ROCKET MOTOR Filed Aug. 5, 1951 a Sheets-Sheet? Lyman/es: S/D/VEY 4LL DF/V/YIJ Hz/ADE/V United States Patent" MIXED FUEL CGNTRIBL SYSTEM FOR A ROCKET MQTGR Sidney Allen and Dennis Hurden, Park Side, Coventry,

England, assignors to Armstrong Siddeley Motors Limited, Coventry, England Application August 3, 1951, Serial No. 240,216

Claims priority, application Great Britain September 8, 1950 8 Claims. (Cl. 60-39.14)

This invention relates to a control system for a rocket motor of the kind having igniter equipment and combustion equipment for a mixture of a liquid fuel (for example, methyl alcohol and water) and liquid oxidizer (for example, liquid oxygen or nitric acid) forming the propellent, and a pump and valve means both for the fuel and for the oxidizer.

The main object is to ensure satisfactory and economical operation of the motor.

According to the invention, when the motor is to be operated the oxidizer system (through the pump as far as the associated valve means) is first supplied with liquid oxidizer whereby to cool the oxidizer system and initiate the priming of the oxidizer pump, and the fuel pump will not commence delivery until after the oxidizer pump has attained a stable delivery to a by-pass leading back to a reservoir for the oxidizer.

Preferably the fuel pump is automatically caused to effect delivery only on the operation of a time-delay switch which is energized when the outlet pressure of the oxidizer pump reaches a predetermined value. The fuel pump, on commencing delivery, may immediately deliver to the igniter equipment, the oxidizer pump being automatically caused to deliver to the igniter equipment only when the outlet pressure of the fuel pump reaches a predetermined value.

Preferably, too, when the pressure in the igniter equipment (after combustion has been effected) reaches a predetermined value, both the valve means are partially opened automatically to deliver limited supplies to the combustion equipment; whilst, when full thrust is required, the by-pass for the oxidizer is closed and both the valve means are fully opened to deliver full supplies to the combustion equipment.

For a better understanding of the invention, reference should be directed to the accompanying diagrammatic drawings, in which:

Figures 1 and 2 jointly show a diagram of electrical, pneumatic and other control means according to the invention, Figure 1 fitting to the left of Figure 2;

Figure 3 is a sectional elevation of the valve means for the oxidizer system, such as is described in the specification accompanying co-pending Application Serial No. 240,217; and

Figure 4 is a sectional elevation of the ignition end of the combustion equipment to a larger scale.

Referring first to Figure 3, this shows a casing with an inlet 11 and an outlet 12. The latter is connected with a passage 13 by means of openings 14 in the head of a throttle valve member 15 biassed to the ofi position shown and movable to the open position by the application of fluid pressure to the inlet 16. The passage 13 is shown as shut off from the inlet 11 by the head of a stop valve member 17 biassed to the closed position and movable to the open position by the application of fluid pressure to the inlet 18. 19 is a normallyopen outlet connected to a by-pass pipe 20 (Figure 2) and closable by the head of a valve member 21 when "ice fluid pressure is applied to the inlet 22. 23 is an outlet connected to a pipe 95 (Figure 2) which is hereinafter referred to, the outlet 23 being normally segregated from the inlet 11 by the head of a valve member 24 which is biassed to the closed position shown and movable to the open position by the application of fluid pressure to the inlet 25. Each of the four valve members 15, 17, 21 and 24 has a pressure-responsive plunger 26 operating in a cylinder 27 provided with a venting means 23.

In the diagram of Figures 1 and 2, 31 represents a fuel tank and 32 a liquid oxygen tank, and each is provided with a pressurizing valve 33, 33 which when opened admits a supply of nitrogen from storage Vessels 34, 34 by way of a filter 35, a main pressure reducing valve 36, and two subsidiary reducing valves 37, 37. The oxygen tank is additionally provided with a safety valve, indicated at 38.

represents a further reducing valve through which nitrogen is delivered through a non-return valve 41 to a control valve 44, and directly to a drier and cleaner 43.

When it is expected that the service of the rocket motor will shortly be required, the first step to be taken involves operating the control valve 44 whereby nitrogen at an appropriate pressure is delivered to a pneumatic actuator 45 by means of which a valve 46, at the outlet side of the oxygen tank 32, is opened. The oxygen is then free to flow by gravity through the oxygen pump, indicated at 47, and along the outlet line 48 leading to the inlet 11 of combined stop and throttle valve means 49, shown in detail in Figure 3. The pressure-responsive valve So (having the valve member 21) is open to connect the inlet 11 with the by-pass return pipe 26 leading back to the upper end 51 of the oxygen tank 32. Joining this pipe 20 is a further by-pass pipe 52 connecting with the highest point of the pump 47, whereby to permit the removal of any vaporised liquid oxygen so as to initiate the priming of the pumpthis by-pass pipe 52 including a pressure-responsive valve 53 connected by a pipe 54 to be operated from the output side of the pump so as to close the passage of the pipe 52 when the output of the pump reaches a predetermined value, as disclosed in the specification of co-pending patent application Ser. No. 242,555, filed August 18, 1951.

In ordinary conditions the cooling of the oxygen system by this means, and the return of most of the evaporated oxygen to the tank 32, will require a minimum of about five minutes, this cooling being necessary to ensure that a subsequent flow of liquid oxygen shall remain in the liquid form.

In order to fire the rocket: After the oxygen system has been cooled as aforesaid a master switch 56 is operated, and this completes a circuit through a switch 57 and conductors 58 and 59 for an electrically operated valve 60 to supply nitrogen passed by the reducing valve 40 to the two pressurizing valves 33 by way of the pipes 61, 62 and 63, whereby to open these pressurizing valves. (Obviously, however, the pressurizing valve for the fuel tank could, if preferred, be opened later.) In addition nitrogen released by the valve 69 is also applied to a pneumatic device 64, from the pipe 63, whereby a clutch 65 is engaged, the engagement of the clutch serving mechanically to connect both the oxygen pump 47 and the fuel pump 66 to appropriate driving means (not shown).

The oxygen pump, being already primed with liquid, starts working and immediately develops a pre-determined pressure, whereupon a pressure-operated two-way switch 68, associated with its output, is operated to energize the coil 69 of a known form of time-delay switch 70 by way of the conductor 71, switch 68, conductors 72, 73, 74, and switch and the switch 79 will operate after, say, about four seconds-this delay being advisable in the sequence of operation in order to allow the oxygen pump to stabilize itself before the oxygen flow is disturbed. Until the end of this period of delay the oxygen is pumped through the by-pass valve 50 (Figure 2) back to the tank 32 as previously described.

The operation of the switch 70, after the predetermined delay, completes a circuit. by way of conductors 71, switch 68, and conductors 72, 76 and 77, for an operating coil 78 to open a valve 79 at the outlet side of the fuel tank 31. (The valve 79 is closed by another operating coil 80. when the pressure-operated switch .68 is in the position shown in Figure 1, by way of conductor 71,'switch 68 and conductor 80a.) This allows fuel to flow into the pump 66 which then starts delivering fuel along a pipe 81 to the inlet side of a stop and throttle valve means 82, which is in general similarto that of Figure 3. The valve means 82 passes some of the fuel through a normally-open, pressure-operated by-pass 83 (like the'valve 50) to waste at 84, and, in parallel, along a V pipe 85 to the igniter equipment, indicated at 86. The

latter may be arranged as disclosed in the specification of co-pending patent application No. 240,197, now Patent'No. 2,701,445.

When the fuel pump has developed a pre-determined pressure, a pressure-operated switch 87 closes to provide a circuit from the conductor 58 through conductors 59a, 88, 89 for the coil of a solenoid-operated valve 90, the circuit being completed by a conductor. 90a .connected to conductor 74. Valve 90 consequently opens to supply nitrogen along pipes 61, 91 and 92 to open a normally-closed valve 93 (valve member 24) of the valve means 49, in consequence of which a small supply of oxygen is delivered along the line 95 to the igniter equipment 86. The closure of both 'the pressureoperated switches 68, 87 also effects the energizing of a booster coil 97, by way of the conductors 88 and 98 and switch 99, by means of which a sparking plug or the like for the igniter equipment is energized.

When ignition occurs in the igniter equipment, a pressure builds up in the interior thereof, and in due course a the pressure-operated switch 99 is operated to break the circuit through the booster coil 97 and to close a circuit by way of the conductor 101 to energize the solenoidoperated valve 102. This valve then supplies pressure from the pipe 61 along the pipes 103, 104 to the pressure-operated by-pass valve 83 whereby to close this fuel valve, and by pipes 105 to the stop valves (valve member 17) in the valve means 49 and 82, whereby to open 7 them. In consequence a predetermined quantity of'each propellent ingredient is delivered through the openings 14 in the still closed throttle valve members 15 to the combustion equipment,.indicated at 107, along the pipes 108 and 109. A portion of the oxygen therefore enters the'combustion chamber directly througha ring of holes 110, and a portion of the fuel, after circulating round the cooling jacket space 111 round the combustion chamber 112, .travels along a pipe 113 to the annular space 114, to enter the chamber through a ring of holes 115. These two ingredients are then ignited in the combustion chamber by a pencil of flame issuing from the nozzle 116 of the igniter equipment 86.-

The rocketmotor is now operating, and the rise of pressure in the combustion chamber operates the pressure-operated switch 75 to de-energize the coil of the solenoid-operated valve 90, in consequence of which the valve 93 closes under its bias to cut off the supply of oxidizer to the igniter equipment. Atthe same time the coil 69 of the time-delay switch 70 is de-energized to allow this to re-set for the next start of the motor. The operation of the switch 75 also builds up part of a circuit, through the conductor 118, for the control of the throttle valves of the valve means 49 and 82.

The propellent supplied to the .rocket motor during this period isonly, say, one-third of the total available, such as to give only a minimum thrust. At any time that full thrust is required, a switch 119 is closed. This It should be noted that the system isentirely automatic and that no step may be taken until the previous.

one has been completed. For instance, unless both pumps are delivering their full pressure, the ignition equipment will not fire; and until ignition has been effected the main stop valves (valve member 17) cannot open.

To stop the motor, the main switch 56 can be opened (i. e., moved to the position shown, in which case the switch 68 will also move to the position shown to close the fuel valve 79), or an emergency switch 124 operated to open the switch 57. The full thrust switch 119 should also be opened, but no harm will result if it is left closed,

since the pressure-operated switch 75 will ensure that the throttle valves will remain closed on the next attempt to start the motor until the combustion equipment is.

operating, when the switch 75 will be actuated and the rocket motor will again run at full thrust.

125 represents a dump valve, as disclosed in the specification of co-pending patent specification No. 240,725,

now PatentNo. 2,664,701, which is operated by pressure supplied along the pipe 126 from the delivery side of the fuel pump.

What we claim as our invention and desire to secure V by Letters Patent of the United States is:

1. A control system for a rocket motor of the kin 'having igniter equipment and combustion equipment pump and the latter to the oxidizer valve means respec-.

' tively, the oxidizer pump being of the kind which will allow a fiow through it when it is not being operated; including an additional valve interposed in the conduit connecting the oxidizer reservoir to the associated pump, the oxidizer pump and the associated valve means being arranged at a level to be supplied with oxidizer by gravity when said additional valve is open in order to cool these parts to a temperature at which evaporation ceases, a conduit extending from the oxidizer valve means to the associated reservoir to return evaporated oxidizer to the reservoir and, when the oxidizer pump is running, to initially return its output to the oxidizer reservoir, means responsive to the pressure of the output of the oxidizer pump, a valve in the conduit interconnecting the fuel reservoir and the associated pump, and delay means for actuating said last-mentioned valve from said pressureresponsive means after the pressure of the output of the oxidizer pump reaches a predetermined value.

2. A-control system for a rocket motor of the kind having igniter equipment and combustion equipment for a mixture of liquid fuel and liquid oxidizerforming the propellent, a reservoir, pump and valve means for the fuel and conduits connecting the reservoir to the pump and the pump to the valve means respectively, a reservoir, pump and valve means for the oxidizer and conduits connecting the oxidizer reservoir to the oxidizer pump and the latter to the oxidizer valve means respectively, and conduits respectively connecting both of said valve means both to said igniter equipment and to said combustion equipment, the oxidizer pump being of the kind which will allow a flow through it when it is stationary; including an additional valve inthe conduit between the oxidizer pump and its associated reservoir, the oxidizer pump and its associated valve means being placed relatively to the oxidizer reservoir so that oxidizer can flow through the pump to the valve means for the oxidizer when said additional valve is opened to cool these parts to a temperature at which evaporation ceases, a conduit from the valve means for the oxidizer leading to the oxidizer reservoir to return to the latter the vaporized oxidizer which results from the cooling of the pump and the associated valve means and which serves also to initially return to the oxidizer reservoir the liquid oxidizer output of the associated pump when the latter is running, an electric switch responsive to a predetermined pressure in the output of the oxidizer pump, a time delay device connected to said switch, and a solenoid valve operable by said time 'delay device after a predetermined time lag, said solenoid valve disposed in the conduit interconnecting the fuel pump and the fuel reservoir.

3. A control system for a rocket motor of the kind having igniter equipment and combustion equipment for a mixture of liquid fuel and liquid oxidizer forming the propellent, a reservoir, pump and valve means for the fuel, and a reservoir, pump and valve means for the oxidizer; including an additional valve between the oxidizer reservoir and the associated pump for enabling oxidizer to be supplied through the pump to the valve means for the oxidizer in order to cool the oxidizer pump and its associated parts to a temperature at which the evaporation ceases, whereby to prime the pump, a bypass extending from said oxidizer valve means whereby, when said oxidizer pump is running, to return its output to said oxidizer reservoir, a pressure-operated electric switch, an electrically-operated time delay device and a solenoid-operated valve, the latter being in the connection between said fuel reservoir and said fuel pump and being actuated to establish the supply when said time delay device has operated, said pressure-operated switch connected to be subject to the delivery pressure of said oxidizer pump whereby, when a predetermined delivery pressure is reached, to energise said time delay device, both pumps in those conditions delivering to their respective valve means, and the fuel valve means delivering to a by-pass and to the igniter equipment, said oxidizer valve means including a pressure-responsive valve biassed to isolate said igniter equipment from the oxidizer pump output, a second pressure-operated switch and a second solenoid-operated valve, said second solenoid-operated valve normally interrupting a pressure supply to said pressure-responsive valve, said second pressure-operated switch connected to be subject to the delivery pressure of said fuel pump whereby, when a predetermined output pressure is reached, to energise said second solenoid-operated valve and thereby cause said pressure-responsive valve to open against its bias for delivering oxidizer to said igniter equipment.

4. A control system, according to claim 3, in which both said valve means include further pressure-responsive valves biassed to isolate said combustion equipment from the output of both said pumps, a third pressureoperated switch and a third solenoid-operated valve, said third solenoid-operated valve normally interrupting a pressure supply to said further valves, said third pressureoperated switch connected to be subject to the internal pressure of said ignition equipment whereby, when a predetermined internal pressure is reached, to energise said third solenoid-operated valve and thereby cause said further valves to open against their biases for delivering, through respective constrictor valves, a limited supply of oxidizer and fuel to said combustion equipment, the remainder of the outputs of both pumps being delivered to respective by-passes.

5. A control system, according to claim 4, in which both constrictor valves are biassed to close respective unconstricted communications to said combustion equipment and have ducts in them providing the constrictions,

pressure-responsive means respectively associated with said constrictor valves for moving them against their biases, a pressure-responsive valve controlling the bypass of said oxidizer valve means, and a manually operable switch and an associated solenoid valve, the latter when energised opening a pressure supply to the pressure-responsive valve of the by-pass of said oxidizer valve means whereby to close said by-pass, and also applying said pressure supply to both said pressure-responsive means for moving said constrictor valves to open said unconstricted communications whereby to deliver a fuel supply of fuel and oxidizer to said combustion equipment.

6. A control system for a rocket motor of the kind having igniter equipment and combustion equipment for a mixture of liquid fuel and liquid oxidizer forming the propellent, a reservoir, pump and valve means for the fuel, and a reservoir, pump and valve means for the oxidizer; including an additional valve between the oxidizer reservoir and the associated pump for enabling oxidizer to be supplied through the pump to the valve means for the oxidizer in order to cool the oxidizer pump and its associated parts to a temperature at which the evaporation ceases, whereby to prime the pump, control means actuable for starting both pumps, a by-pass through which the oxidizer pump delivery is returned to said oxidizer reservoir until a predetermined delivery pressure is reached, time delay means operating responsively to said predetermined delivery pressure for establishing a supply from said fuel reservoir to said fuel pump, means operating responsively to a predetermined outlet pressure of said fuel pump for establishing a supply from both said pumps to said igniter equipment for combustion therein, said fuel valve means including a by-pass for the proportion of the output of said fuel pump which is not delivered to said igniter equipment, means responsive to a predetermined pressure in said igniter equipment for closing said fuel valve by-pass and for operating both said valve means to deliver limited supplies from both pumps to said combustion equipment, and means brought into operation manually for closing said oxidizer pump by-pass and for operating both said valve means for delivering the total outputs from both pumps to said combustion equipment.

7. A control system for a rocket motor of the kind having igniter equipment and combustion equipment for a mixture of liquid fuel and liquid oxidizer forming the propellent, a reservoir, pump and valve means for the fuel, and a reservoir, pump and valve means for the oxidizer; including an additional valve between the oxidizer reservoir and the associated pump for enabling oxidizer to be supplied through the pump to the valve means for the oxidizer in order to cool the oxidizer pump and its associated parts to a temperature at which the evaporation ceases, whereby to prime the pump, control means actuable for starting up both pumps and for connecting a source of pressure to pressurize both reservoirs, a bypass through which the oxidizer pump delivery is returned to said oxidizer reservoir until a predetermined delivery pressure is reached, time delay means operating responsively to said predetermined delivery pressure for establishing a supply from said fuel reservoir to said fuel pump, a bypass through which the fuel pump delivery is returned to said fuel reservoir, ignition means for said igniter equipment, means operating responsively to a predetermined outlet pressure of said fuel pump for establishing a supply from both said pumps to said igniter equipment and for energising said ignition means, means responsive to a predetermined pressure in said igniter equipment for de-energizing said ignition means, for closing said fuel bypass and for operating both said valve means to deliver limited supplies from both pumps to said combustion equipment, and means brought into operation by a manual control for closing said oxidizer pump by-pass and for operating both said valve means for delivering the total outputs from both pumps to said combustion equipment.

' 8. A control system for a. rocket motor of the kind having igniter equipment and combustion equipment for a mixture of liquid fuel and liquid oxidizer forming the propellent, a pump and a valve means both for the fuel and for the oxidizer, and a reservoir for the oxidizer, including'means for initially supplying liquid oxidizer from the reservoir through the oxidizer pump to the valve means for the oxidizer, a by-pass pipe from the oxidizer valve means to the reservoir, means 'for subsequently starting up both the pumps, and means for preventing the fuel pump from commencing delivery. until the oxidizer pump has attained a constant delivery of liquid oxidizer to the by-pass;

References Cited in the file of this patent UNITED. STATES PATENTS 2,395,113 Goddard Feb. 19, 2,397,657 Goddard Apr. 2, 1946 2,469,678 Wyman May 10, 1949 2,470,564 Lawrence May 17, 1949 Wyld et al. Aug. 23, 1949 

1. A CONTROL SYSTEM FOR A ROCKET MOTOR OF THE KIND HAVING IGNITER EQUIPMENT AND COMBUSTION EQUIPMENT FOR A MIXTURE OF LIQUID FUEL AND LIQUID OXIDIZER FORMING THE PROPELLENT, A RESERVOIR, PUMP AND VALVE MEANS FOR THE FUEL, CONDUITS CONNECTING THE RESERVOIR TO THE PUMP AND THE PUMP TO THE VALVE MEANS RESPECTIVELY, AND A RESERVOIR, PUMP AND VALVE MEANS FOR THE OXIDIZER, AND CONDUITS CONNECTING THE OXIDIZER RESERVOIR TO THE OXIDIZER PUMP AND THE LATTER TO THE OXIDIZER VALVE MEANS RESPECTIVELY, THE OXIDIZER PUMP BEING OF THE KIND WHICH WILL ALLOW A FLOW THROUGH IT WHEN IT IS NOT BEING OPERATED; INCLUDING AN ADDITIONAL VALVE INTERPOSED IN THE CONDUIT CONNECTING THE OXIDIZER RESERVOIR TO THE ASSOCIATED PUMP, THE OXIDIZER PUMP AND THE ASSOCIATED VALVE MEANS BEING ARRANGED AT A LEVEL TO BE SUPPLIED WITH OXIDIZER BY GRAVITY WHEN SAID ADDITIONAL VALVE IS OPEN IN ORDER TO COOL THESE PARTS TO A TEMPERATURE AT WHICH EVAPORATION CEASES, A CONDUIT EXTENDING FROM THE OXIDIZER VALVE MEANS TO THE ASSOCIATED RESERVOIR TO RETURN EVAPORATED OXIDIZER TO THE RESERVOIR AND, WHEN THE OXIDIZER PUMP IS RUNNING, TO INITIALLY RETURN ITS OUTPUT TO THE OXIDIZER RESERVOIR, MEANS RESPONSIVE TO THE PRESSURE OF THE OUTPUT OF THE OXIDIZER PUMP, A VALVE IN THE CONDUIT INTERCONNECTING THE FUEL RESERVOIR AND THE ASSOCIATED PUMP, AND DELAY MEANS FOR ACTUATING SAID LAST-MENTIONED VALVE FROM SAID PRESSURERESPONSIVE MEANS AFTER THE PRESSURE OF THE OUTPUT OF THE OXIDIZER PUMP REACHES A PREDETERMINED VALUE.
 8. A CONTROL SYSTEM FOR A ROCKET MOTOR OF THE KIND HAVING IGNITER EQUIPMEWNT AND COMBUSTION EQUIPMENT FOR A MIXTURE OF LIQUID FUEL AND LIQUID OXIDIZER FORMING THE PROPELLENT, A PUMP AND A VALVE MEANS BOTH FOR THE FUEL AND FOR THE OXIDIZER, AND A RESERVOIR FOR THE OXIDIZER, INCLUDING MEANS FOR INITIALLY SUPPLYING LIQUID OXIDIZER FROM THE RESERVOIR THROUGH THE OXIDIZER PUMP TO THE VALVE MEANS FOR THE OXIDIZER, A BY-PASS PIPE FROM THE OXIDIZER VALVE MEANS TO THE RESERVOIR, MEANS FOR SUBSESQUENTLY STARING UP BOTH THE PUMPS, AND MEANS FOR PREVENTING THE FUEL PUMP FROM COMMENCING DELIVERY UNTIL THE OXIDIZER PUMP HAS ATTAINED A CONSTANT DELIVERY OF LIQUID OXIDIZER TO THE BY-PASS. 